- Industry: Telecommunications
- Number of terms: 29235
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ATIS is the leading technical planning and standards development organization committed to the rapid development of global, market-driven standards for the information, entertainment and communications industry.
In video systems, temporally varying visual imagery intended to communicate or to convey movement or change.
Industry:Telecommunications
In video systems, the average level of the picture signal during active scanning time integrated over a frame period; defined as a percentage of the range between blanking and reference white level.
Industry:Telecommunications
In video systems, the one-way transmission path between two designated points.
Industry:Telecommunications
In video systems, the perceived impairments associated with a scene cut.
Industry:Telecommunications
In video technology and image processing, a process for the selective overlay of one video image upon another, as through chroma key. Note: Control of the ratio of foreground to background determined by the specifications derived from luminance information, and provided in the linear key data. Ratios to be applied are carried for each picture element in the alpha channel. The process permits realistic rendering of semi-transparent objects.
Industry:Telecommunications
In video technology, a technique used to improve contrast and picture clarity by flattening the camera response to 400 lines (by aperture correction) and applying an additional correction to increase the depth of modulation in the range of 250 to 300 lines (in an NTSC system,) both vertically and horizontally. Note: Image enhancement produces a correction signal with symmetrical overshoots around transitions in the picture, but it must be used sparingly if natural appearance is to be maintained.
Industry:Telecommunications
In video technology, that point on the chromaticity diagram having the tristimulus of a source appearing white under the viewing conditions; i.e., a spectrally nonselective sample under the illumination of viewing conditions.
Industry:Telecommunications
In video, a form of block distortion where one or more blocks in the image bear no resemblance to the current or previous scene and often contrast greatly with adjacent blocks.
Industry:Telecommunications
In video, a peak excursion of the picture signal in the white direction.
Industry:Telecommunications
In video, an image coding system that derives a luminance signal and two bandwidth-limited color-difference signals, to provide luminance information that is encoded into one signal supplemented by, but totally independent of, two color signals carrying only chrominance information, i.e., hue and saturation. Note 1: Constant luminance is only achieved when the luminance and chrominance vectors are derived from linear signals. The introduction of nonlinear transform characteristics (usually to achieve a better signal-to-noise ratio and to control dynamic range prior to bandwidth reduction) before creating the luminance and chrominance vectors destroys constant luminance. Current video systems do not reconstitute the luminance and chrominance signals in their linear form before further processing and, therefore, depart from constant luminance. Note 2: When R,G,B information is required to be recovered from the set of luminance and color-difference signals, the values correlated to the original signals are obtained only if the luminance and chrominance signals have been derived from linear R,G,B functions or have been transformed back to linear. Note 3: Constant luminance not only provides a minimum of subjective noise in the display (since the luminance channel does not respond to chrominance noise,) but also preserves this noise minimum through chrominance transformations.
Industry:Telecommunications
